The intent of this proposal is to establish a high speed, x-ray diffraction data collection system for protein crystallographic investigations at the University of Texas at Austin. The instrument requested is similar to the MARK II Multiwire Area Detector Diffractometer System developed by Drs. Nguyen huu Xuong and Ron Hamlin at UCSD that has revolutionized the collection of x-ray diffraction data. It has been demonstrated that x-ray diffraction data for macromolecular systems can be collected using such an instrument at rates up to 100 times that possible using a standard autodiffractometer. Two regional resource area detector facilities are presently in operation, one at UCSD on the west coast and the other in Virginia on the east coast. The facility we are proposing could meet the needs of four NIH supported research groups on the University of Texas at Austin campus, four other NIH supported research programs from nearby campuses, and would still allow time available for other NIH investigators from other institutions. There are many arguments for locating a shared resource area detector system at UT-Austin: the P.I.'s research group has used the UCSD facility three times and is familiar with its operation; laboratory personnel are already in place that are qualified to properly operate and maintain both the hardware and software of the facility; space is available in the P.I.'s laboratory and an existing rotating anode can be used as part of the system; UT-Austin campus has three biomolecular crystallographers, several other research groups are within convenient driving distance, and easy access to Austin is provided by several major airlines; UT-Austin has excellent machine shop, instrument design, and computer service personnel on campus; UT-Austin is likely to acquire a supercomputer which would be a complimentary resource on campus of great value to this user group; and The University of Texas at Austin recognizes the value of this facility and has agreed to provide matching funds for the acquisition of the area detector x-ray diffractometer.